1. Field of the Invention
The present invention relates to an ink-jet recording head using an ink-jet recording system.
2. Description of the Related Art
Conventionally, recording head structures of commercially-available thermal ink jet printers mostly utilize a laminated structure of tantalum (Ta) and an insulating film (SiN or SiO2 film), as a heater protective film 102 on the surface of a heater 100 (see FIG. 3).
However, due to the heater protective film 102 (a tantalum laminated film) being formed on the surface of the heater 100, heat transmission from the heater 100 to ink is interfered by the heater protective film 102 (the tantalum laminated film), and energy efficiency (that is, a ratio at which input electric energy is converted to ink boiling energy) deteriorates, thereby resulting in an increase of electric power consumption.
For this reason, a structure as shown in FIG. 4 has been proposed in which a self-oxidized (protective) film 106 is formed on a heating resistor 104 (which is made out of TaSiO, CrSiO or the like) which serves as a heater, and the heater protective film 102 made of a tantalum laminated film as shown in FIG. 3 is not required (for example, see Japanese Patent Application Laid-Open (JP-A) No. 6-71888, FIG. 1; and JP-A No. 6-238901, FIG. 1).
Further, a technique is proposed in which nickel (Ni), nickel-gold (Ni+Au) are used as conductive layer materials so as to prevent a conductive layer 108 used to connect the heater 104 from being corroded by ink (for example, see JP-A No. 6-71888; JP-A No. 9-300623, FIG. 1; and JP-A No. 10-16242, FIG. 1).
However, nickel or a nickel compound has been known as a cancerating substance and has become a regulated substance based on Pollutant Release and Transfer Register Act. Thus, many restrictions are placed on these materials from the aspect of safety and environment. Therefore, it is not desirable to use them as industrial products in the future. On the other hand, aluminum conductive layer material is generally used as semiconductor process material, and workability and handling thereof are easy.
In a case in which aluminum is merely used in place of nickel, nickel-gold, only an oxide film having a film thickness of about 0.5 to 1.0 μm makes it possible to protect aluminum conductive layer material from corrosion by ink. This has a problem in terms of reliability.